WO2023072155A1 - Rfid读卡电路和电子设备 - Google Patents

Rfid读卡电路和电子设备 Download PDF

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Publication number
WO2023072155A1
WO2023072155A1 PCT/CN2022/127732 CN2022127732W WO2023072155A1 WO 2023072155 A1 WO2023072155 A1 WO 2023072155A1 CN 2022127732 W CN2022127732 W CN 2022127732W WO 2023072155 A1 WO2023072155 A1 WO 2023072155A1
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Prior art keywords
coil
signal
rfid
processor
circuit
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PCT/CN2022/127732
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English (en)
French (fr)
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李志光
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维沃移动通信有限公司
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Publication of WO2023072155A1 publication Critical patent/WO2023072155A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10198—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves setting parameters for the interrogator, e.g. programming parameters and operating modes

Definitions

  • the application belongs to the technical field of radio frequency identification, and in particular relates to an RFID card reading circuit and electronic equipment.
  • Radio Frequency Identification (RFID) technology is a near-field communication identification technology with a carrier frequency of 125K-135K. Because of its low cost and fast identification, it has a large number of applications in access control, traffic and other scenarios.
  • RFID Radio Frequency Identification
  • Wireless charging technology in electronic devices is a wireless energy transmission technology based on a carrier frequency of 110K-190KHz. In order to achieve correct energy transmission, it is also accompanied by communication technology.
  • radio frequency identification circuits which easily leads to a large circuit layout area, that is, the built circuit occupies a large area.
  • the purpose of the embodiments of the present application is to provide an RFID card reading circuit and electronic equipment, which can solve the problem that the existing radio frequency identification circuit occupies a large area.
  • the RFID card reading circuit includes: an RFID coil, a coil drive circuit, a coil resonant capacitor and an envelope detection circuit, wherein,
  • the first end of the RFID coil is connected to the output end of the coil drive circuit, the input end of the coil drive circuit is connected to the first control end of the processor in the electronic device, and the coil drive circuit is used to receive the processing
  • the induction magnetic field used to sense the external card is formed under the action of the card;
  • One end of the coil resonant capacitor is connected to the second end of the RFID coil, and the other end of the coil resonant capacitor is electrically connected to the low voltage end;
  • the input end of the envelope detection circuit is connected to the second end of the RFID coil, and the output end of the envelope detection circuit is connected to the receiving end of the processor through the audio codec in the electronic device, so
  • the envelope detection circuit is used to filter the carrier signal in the signal output from the second end of the RFID coil to obtain a baseband signal, and output the baseband signal to the audio codec.
  • the audio codec includes a plurality of microphone interfaces
  • the output end of the envelope detection circuit is connected to the target microphone interface, the output end of the audio codec is connected to the receiving end of the processor, and the target microphone interface is any interface in the plurality of microphone interfaces ;
  • the envelope detection circuit is used to transmit the baseband signal to the audio codec through the target microphone interface.
  • the RFID card reading circuit also includes a first switch
  • the output end of the envelope detection circuit is connected to the first selection end of the first switch, the fixed end of the first switch is connected to the target microphone interface of the audio codec, and the second selection end of the first switch is
  • the terminal is connected to a microphone, the target microphone interface is any one of a plurality of microphone interfaces of the audio codec, and the second control terminal of the processor is connected to the control terminal of the first switch;
  • the first switch is used to receive a control signal provided by the processor through its second control terminal, and control the connection state of the first switch according to the control signal, and connect the first selection terminal with the
  • the envelope detection circuit is connected to the audio codec through the first switch, and the baseband signal is transmitted to the audio codec through the first switch.
  • the second selection terminal is connected to the fixed terminal, the microphone is connected to the audio codec through the first switch, and the output signal of the microphone is transmitted to the audio codec through the first switch. codec.
  • the audio codec also includes a codec, a first analog-to-digital converter, a first operational amplifier, and a multiplexer;
  • the target microphone interface is connected to the input end of the first operational amplifier through the multi-way switch, the output end of the first operational amplifier is connected to the input end of the first analog-to-digital converter, and the first The output end of the analog-to-digital converter is connected to the first input end of the codec, and the output end of the codec is connected to the receiving end of the processor;
  • the target microphone interface When the target microphone interface is connected to the input end of the first operational amplifier through the multi-way switch, the target microphone interface transmits the baseband signal output from the output end of the envelope detection circuit to the The input terminal of the first operational amplifier, the first operational amplifier is used to amplify the baseband signal and transmit it to the first analog-to-digital converter, and the first analog-to-digital converter is used to amplify the amplified Perform analog-to-digital conversion on the baseband signal to obtain a first target digital signal, and transmit the first target digital signal to the codec, and the codec is used to decode the first target digital signal and then transmit to the processor.
  • the audio codec further includes N second analog-to-digital converters and N second operational amplifiers, the codec includes N second input terminals, and N is a positive integer;
  • Any microphone interface in the remaining microphone interfaces is connected to the input end of a second operational amplifier through the multi-way switch, and the output end of a second operational amplifier is connected to the codec through a second analog-to-digital converter.
  • One second input terminal, and the second analog-to-digital converters connected to the output terminals of the N second operational amplifiers are different, and the second input terminals connected to the N second analog-to-digital converters are different, the The remaining microphone interfaces are interfaces other than the target microphone interface among the plurality of microphone interfaces;
  • the second operational amplifier is used for any one of the remaining microphone interfaces
  • the signal transmitted by the microphone interface is amplified, and the second analog-to-digital converter is used to perform analog-to-digital conversion on the amplified signal output by the second operational amplifier to obtain a second target digital signal, and convert the second target digital signal to
  • the signal is transmitted to the codec, and the codec is used to decode the second target digital signal and transmit it to the processor.
  • the coil drive circuit includes an N-type metal oxide semiconductor NMOS transistor and a P-type metal oxide semiconductor PMOS transistor;
  • the gate of the NMOS transistor is connected to the first control terminal of the processor, the first pole of the NMOS transistor is grounded, the second pole of the NMOS transistor is connected to the first pole of the PMOS transistor, and the PMOS transistor
  • the gate of the gate is connected to the first control terminal of the processor, and the second pole of the PMOS transistor is connected to the power supply, wherein the first terminal of the RFID coil is connected to the second pole of the NMOS transistor in the coil drive circuit And the first pole of the PMOS transistor is connected.
  • the coil drive circuit includes an NPN transistor and a PNP transistor;
  • the base of the PNP transistor is connected to the first control terminal of the processor, the first pole of the PNP transistor is grounded, the second pole of the PNP transistor is connected to the second pole of the NPN transistor, The base of the NPN transistor is connected to the first control terminal of the processor, and the first pole of the NPN transistor is connected to the power supply, wherein the first end of the RFID coil is connected to the second terminal of the PNP transistor. pole and the second pole of the NPN transistor.
  • the envelope detection circuit includes a first diode, a second diode, a third diode, a first resistor, a second resistor, a first capacitor, a second capacitor and a third capacitor;
  • the anode of the first diode is connected to the second end of the RFID coil, and the cathode of the first diode is respectively connected to one end of the first resistor, one end of the first capacitor, and the second end of the first capacitor.
  • One end of the two capacitors is connected, the other end of the first resistor is grounded, the other end of the first capacitor is grounded, and the other end of the second capacitor is respectively connected to one end of the second resistor, one end of the third capacitor,
  • the cathode of the second diode is connected to the anode of the third diode, the other end of the second resistor, the other end of the third capacitor, the anode of the second diode and the first
  • the cathodes of the three diodes are all grounded, and the cathode of the second diode is connected to the receiving end of the processor through the audio codec.
  • the RFID card reading circuit further includes a third resistor, and the second end of the RFID coil is connected to the anode of the first diode through the third resistor.
  • the embodiment of the present application further provides an electronic device, including an audio codec, a processor, and the above-mentioned RFID card reading circuit.
  • the coil driving circuit is used to receive the driving signal, and output the first voltage signal to the first end of the RFID coil under the action of the driving signal
  • the RFID coil is used to receive the first voltage signal under the action of the first voltage signal.
  • An induction magnetic field for inducting an external card is formed, and the envelope detection circuit is used to filter the carrier signal in the signal output from the second end of the RFID coil to obtain a baseband signal, and output the baseband signal to the audio codec.
  • the input end of the envelope detection circuit is connected to the second end of the RFID coil, and the output end of the envelope detection circuit is connected to the receiving end of the processor through the audio codec in the electronic device, so as to realize the
  • the filtered baseband signal is transmitted to the processor through the audio codec, that is, the solution of this embodiment does not need to use additional discrete components, and the envelope detection circuit multiplexes the audio codec in the electronic device and the receiving end of the processor Connecting and multiplexing the functions in the audio codec to process the output signal of the envelope detection circuit and then transmit it to the processor, which can reduce the number of components in the circuit, thereby reducing the area occupied by the circuit.
  • Fig. 1 is one of the structural diagrams of the RFID circuit that the embodiment of the present application provides;
  • Fig. 2 is the second structural diagram of the RFID circuit provided by the embodiment of the present application.
  • Fig. 3 is the third structural diagram of the RFID circuit provided by the embodiment of the present application.
  • Fig. 4 is one of the structural diagrams of the coil driving circuit in the RFID circuit provided by the embodiment of the present application.
  • Fig. 5 is the second structure diagram of the coil driving circuit in the RFID circuit provided by the embodiment of the present application.
  • Fig. 6 is a structural diagram of the envelope detection circuit in the RFID circuit provided by the embodiment of the present application.
  • Fig. 7 is a kind of speech signal diagram of microphone recording
  • FIG. 8 is a diagram of a baseband signal output by the second end of the envelope detection circuit in the RFID circuit provided by the embodiment of the present application;
  • FIG. 9 is a structural diagram of an audio codec provided by an embodiment of the present application.
  • the present application provides a radio frequency identification RFID card reader circuit of an embodiment, the RFID card reader circuit includes: RFID coil 110, coil drive circuit 120, coil resonant capacitor 130 and envelope detection circuit 140, wherein ,
  • the first end of the RFID coil 110 is connected to the output end of the coil drive circuit 120, the input end of the coil drive circuit 120 is connected to the first control end of the processor 220 in the electronic device, and the coil drive circuit 120 is used for receiving the processor 220 through the first The drive signal provided by the control terminal, and output the first voltage signal to the first end of the RFID coil 110 under the action of the drive signal, and the RFID coil 110 is used to form an induced magnetic field for inducting the external card under the action of the first voltage signal ;
  • One end of the coil resonant capacitor 130 is connected to the second end of the RFID coil 110, and the other end of the coil resonant capacitor 130 is electrically connected to the low voltage end;
  • the input end of the envelope detection circuit 140 is connected with the second end of the RFID coil 110, the output end of the envelope detection circuit 140 is connected with the receiving end of the processor 220 through the audio codec 210 in the electronic equipment, and the envelope detection circuit 140 is used
  • the carrier signal in the signal output from the second end of the RFID coil 110 is filtered to obtain a baseband signal, and the baseband signal is output to the audio codec 210 .
  • the low-voltage terminal may be a DC low-voltage terminal.
  • the low-voltage terminal may be a ground terminal, that is, the other terminal of the coil resonant capacitor 130 may be grounded.
  • the envelope detection circuit 140 can demodulate the low-frequency signal (baseband signal) from the signal output from the second end of the RFID coil 110. It can be understood that the envelope detection circuit 140 has a low-pass filtering function.
  • the coil resonant capacitor 130 will form a resonance with the low-frequency RFID coil 110, and the coil resonant capacitor 130 will appear as a sine wave with a stable amplitude.
  • the oscillation frequency can be 125khz or 135khz, due to the envelope
  • the detection circuit 140 has a low-pass filter function, and the carrier signal (for example, 125khz) will be filtered out.
  • the output of the envelope detection circuit 140 to the audio codec 210 is a straight line, and it can be understood that the baseband signal is empty.
  • the envelope detection circuit 140 After being filtered by the envelope detection circuit 140 , the envelope detection circuit 140 outputs the filtered baseband signal to the audio codec 210 .
  • the audio codec 210 (CODEC) is usually composed of an operational amplifier, an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), etc.
  • microphone 230 (MIC) recording and speaker driving, and can amplify the signal, Analog-to-digital conversion and digital-to-analog conversion, etc., because electronic equipment requires the microphone 230 to pick up sound, so the audio codec 210 is an important configuration on existing electronic equipment.
  • the coil drive circuit 120 is used to receive the drive signal, and output the first voltage signal to the first end of the RFID coil 110 under the action of the drive signal
  • the RFID coil 110 is used to receive the first voltage signal
  • the envelope detection circuit 140 is used to filter the carrier signal in the signal output by the second end of the RFID coil 110 to obtain a baseband signal, and output the baseband signal to the audio codec 210.
  • the input end of the envelope detection circuit 140 is connected to the second end of the RFID coil 110, and the output end of the envelope detection circuit 140 is received by the audio codec 210 and the processor 220 in the electronic device.
  • the envelope detection circuit 140 multiplexes the audio codec in the electronic device
  • the decoder 210 is connected to the receiving end of the processor 220, and the functions in the audio codec 210 are multiplexed to process the output signal of the envelope detection circuit 140 and then transmitted to the processor 220, which can reduce the number of components in the circuit, thereby reducing the circuit Occupy area.
  • the audio codec includes a plurality of microphone interfaces
  • the output end of the envelope detection circuit 140 is connected to the target microphone interface J1, the output end of the audio codec 210 is connected to the receiving end of the processor 220, and the target microphone interface J1 is any interface in a plurality of microphone interfaces;
  • the envelope detection circuit 140 is used to transmit the baseband signal to the audio codec 210 through the target microphone interface J1.
  • the output terminal of the envelope detection circuit 140 multiplexes the target microphone interface J1 of the audio codec 210 of the electronic equipment to transmit the signal output by it to the audio codec 210, and the audio codec 210 is to the envelope received by the target microphone J1
  • the signal output from the output terminal of the detection circuit 140 is processed and then transmitted to the processor 220.
  • the audio codec 210 amplifies the signal and performs analog-to-digital conversion processing on the signal and then transmits it to the processor 220. No additional interface is required to transmit the envelope detection
  • the signal at the output end of the circuit 140 saves circuit cost.
  • each microphone interface can be connected to a corresponding microphone 230 .
  • the RFID card reading circuit also includes a first switch 150;
  • the output end of the envelope detection circuit 140 is connected to the first selection end of the first switch 150, the fixed end of the first switch 150 is connected to the target microphone interface J1 of the audio codec 210, and the second selection end of the first switch 150 is connected to the microphone 230 , the target microphone interface J1 is any one of the multiple microphone interfaces of the audio codec 210, and the second control terminal of the processor 220 is connected to the control terminal of the first switch 150;
  • the first switch 150 is used to receive the control signal provided by the processor 220 through its second control terminal, and control the connection state of the first switch 150 according to the control signal.
  • the network detection circuit 140 communicates with the audio codec 210 through the first switch 150, and the baseband signal is transmitted to the audio codec 210 through the first switch 150.
  • the switch 150 communicates with the audio codec 210 , and the output signal of the microphone 230 is transmitted to the audio codec 210 through the first switch 150 .
  • the output end of the audio codec 210 is connected to the receiving end of the processor 220, and the audio codec 210 can process the signal at the output end of the envelope detection circuit 140 or the output signal of the microphone 230 and transmit it to the receiving end of the processor 220 .
  • the RFID card reading and audio MIC recording functions need to be used in time-sharing.
  • the first switch 150 switches the path of the audio codec 210 to the envelope detection circuit 140 of the RFID circuit to realize the amplification and analog-to-digital conversion of the RFID card reading baseband signal; when voice functions such as recording need to be realized, the processor 220 The first switch 150 is switched to the channel of the main audio microphone 230 to realize the normal voice function.
  • the audio signal is usually in the frequency range of 20 Hz to 20 KHz, and the design of the op amp and the analog-to-digital converter of the audio codec 210 are based on this range, and the signal in the frequency range can be processed Amplify, and realize the analog-to-digital conversion and send it to the processor 220 for processing; while the card reading function of the low-frequency RFID is that after the coil sends out a 125KHz or 134.2KHz carrier wave, the external card forms a load modulation at a rate of about 1.953KHz on the coil induction.
  • the envelope detection circuit 140 When the signal passes through the envelope detection circuit 140 when reading the card, most of the original carrier wave will be filtered out, leaving the baseband signal of 1.953KHz, which is just in the range of 20Hz-20KHz of the aforementioned audio signal, equipped with operational amplifier and modulus Feasibility of converter adoption.
  • FIG. 4 it is a voice signal diagram recorded by a normal microphone 230
  • FIG. 5 it is a baseband signal diagram.
  • the audio codec 210 further includes a codec 211, a first analog-to-digital converter 212, a first operational amplifier 213, and a multiplexer 214;
  • the target microphone interface J1 is connected to the input end of the first operational amplifier 213 through the multi-way switch 214, the output end of the first operational amplifier 213 is connected to the input end of the first analog-to-digital converter 212, and the output of the first analog-to-digital converter 212 The end is connected to the first input end of the codec 211, and the output end of the codec 211 is connected to the receiving end of the processor 220;
  • the target microphone interface J1 When the target microphone interface J1 is connected to the input end of the first operational amplifier 213 through the multi-way switch 214, the target microphone interface J1 transmits the baseband signal output from the output end of the envelope detection circuit 140 to the input of the first operational amplifier 213 end, the first operational amplifier 213 is used to amplify the baseband signal and transmit it to the first analog-to-digital converter 212, and the first analog-to-digital converter 212 is used to perform analog-to-digital conversion on the amplified baseband signal to obtain the first target digital signal, and transmit the first target digital signal to the codec 211 , and the codec 211 is used to decode the first target digital signal and transmit it to the processor 220 .
  • the first operational amplifier 213, the first analog-to-digital converter 212, and the codec 211 in the audio codec 210 are multiplexed, and the first operational amplifier 213 can be used to process the baseband signal. After being amplified, it is transmitted to the first analog-to-digital converter 212, and the first analog-to-digital converter 212 can perform analog-to-digital conversion on the amplified baseband signal to obtain the first target digital signal, and transmit the first target digital signal to the codec 211 , the codec 211 can decode the first target digital signal and transmit it to the processor 220, which can reduce the layout of additional devices, reduce the area occupied by RFID circuits, and the like.
  • the audio codec 210 further includes N second analog-to-digital converters 215 and N second operational amplifiers 216, and the codec 211 includes N second input terminals, N is a positive integer;
  • Any microphone interface J2 in the remaining microphone interfaces is connected to the input end of a second operational amplifier 216 through a multi-way switch 214, and the output end of a second operational amplifier 216 is connected to the codec through a second analog-to-digital converter 215 A second input terminal of 211, and the second analog-to-digital converters 215 connected to the output terminals of the N second operational amplifiers 216 are different, and the second input terminals connected to the N second analog-to-digital converters 215 are different, and the rest
  • the microphone interface is an interface other than the target microphone interface J1 among the plurality of microphone interfaces;
  • the second operational amplifier 216 is used to transmit any microphone interface J2 in the remaining microphone interfaces.
  • the signal is amplified, and the second analog-to-digital converter 215 is used to perform analog-to-digital conversion on the amplified signal output by the second operational amplifier 216 to obtain a second target digital signal, and transmit the second target digital signal to the codec 211 , the codec 211 is configured to decode the second target digital signal and transmit it to the processor 220 .
  • the audio codec 210 can be connected to the envelope detection circuit 140 through the target microphone interface J1, and can be connected to the microphone 230 through the remaining microphone interfaces.
  • the circuit switch 214 When the circuit switch 214 is in communication with the second operational amplifier 216), it is transmitted to the second operational amplifier 216 for amplification, and the second analog-to-digital converter 215 is used to analog the amplified signal output by the second operational amplifier 216
  • the second target digital signal is obtained by digital conversion, and the second target digital signal is transmitted to the codec 211, and the codec 211 is used to decode the second target digital signal and transmit it to the processor 220 to realize normal voice function.
  • the coil driving circuit 120 includes an N-type metal oxide semiconductor NMOS transistor and a P-type metal oxide semiconductor PMOS transistor;
  • the gate G1 of the NMOS transistor is connected to the first control terminal of the processor 220, the first pole S1 of the NMOS transistor is grounded, the second pole D1 of the NMOS transistor is connected to the first pole S2 of the PMOS transistor, and the gate G2 of the PMOS transistor is connected to the processor
  • the first control end of 220 and the second pole D2 of the PMOS transistor are connected to the power supply VCC, wherein the first end of the RFID coil 110 is connected to the second pole D1 of the NMOS transistor and the first pole S2 of the PMOS transistor in the coil driving circuit 120 .
  • the transistors used in all the embodiments of the present application may be triodes, thin film transistors or field effect transistors or other devices with the same characteristics.
  • one pole is called the first pole, and the other pole is called the second pole.
  • the control electrode when the transistor is a thin film transistor or a field effect transistor, the control electrode may be a gate.
  • the first pole may be a drain, and the second pole may be a source; or, the first pole may be a source, and the second pole may be a drain.
  • the first pole may be a source, and the second pole may be a drain.
  • the coil drive circuit 120 is constructed by NMOS transistors and PMOS transistors, and the coil drive circuit 120 outputs a first voltage signal to the first end of the RFID coil 110 through the second pole of the NMOS transistor or the first pole of the PMOS transistor. , making the RFID coil 110 form a magnetic field under the action of the first voltage signal for inducting the external card, so as to ensure the inductive performance of the RFID coil 110 .
  • the coil drive circuit 120 includes an NPN transistor and a PNP transistor;
  • the base B1 of the PNP transistor is connected to the first control terminal of the processor 220, the first pole C1 of the PNP transistor is grounded, the second pole E1 of the PNP transistor is connected to the second pole E2 of the NPN transistor, and the base of the NPN transistor is Pole B2 is connected to the first control terminal of the processor 220, and the first pole C2 of the NPN transistor is connected to the power supply VCC, wherein the first terminal of the RFID coil 110 is connected to the second pole E1 of the PNP transistor and the second pole of the NPN transistor. E2 connection.
  • the control electrode can be a base; the first electrode can be a collector, and the second electrode can be an emitter; or, the first electrode can be an emitter, and the second electrode can be a collector.
  • the first pole may be an emitter, and the second pole may be a collector.
  • the coil drive circuit 120 is constructed by NMOS transistors and PMOS transistors, and the coil drive circuit 120 outputs the first signal to the first end of the RFID coil 110 through the second pole of the PNP transistor or the second pole of the NPN transistor.
  • the voltage signal enables the RFID coil 110 to form a magnetic field under the action of the first voltage signal for inducting external cards, so as to ensure the inductive performance of the RFID coil 110 .
  • the envelope detection circuit 140 includes a first diode 141, a second diode 147, a third diode 148, a first resistor 142, a second resistor 145, a first A capacitor 143, a second capacitor 144 and a third capacitor 146;
  • the anode of the first diode 141 is connected to the second end of the RFID coil 110, and the cathode of the first diode 141 is respectively connected to one end of the first resistor 142, one end of the first capacitor 143 and one end of the second capacitor 144, The other end of the first resistor 142 is grounded, the other end of the first capacitor 143 is grounded, and the other end of the second capacitor 144 is respectively connected to one end of the second resistor 145, one end of the third capacitor 146, the negative pole of the second diode 147 and The anode of the third diode 148 is connected, the other end of the second resistor 145, the other end of the third capacitor 146, the anode of the second diode 147 and the cathode of the third diode 148 are all grounded, the second diode
  • the negative pole of the tube 147 is connected to the receiving end of the processor 220 through the audio codec 210 in the electronic device.
  • the cathode of the second diode 147 is the output terminal of the envelope detection circuit 140 .
  • the envelope detection circuit 140 with the above structure filters the signal output from the second end of the RFID coil 110 to obtain a baseband signal and transmit it to the audio codec 210, which can improve the filtering effect, thereby improving the overall RFID card reading effect.
  • the RFID card reading circuit further includes a third resistor, and the second end of the RFID coil 110 is connected to the anode of the first diode 141 through the third resistor.
  • the signal output from the second end of the RFID coil 110 can first be stepped down by the third resistor, and then transmitted to the envelope detection circuit 140, so as to improve circuit safety.
  • the RFID circuit in the embodiment of the present application is based on the integrated audio codec 210 in the shared electronic equipment, and uses the operational amplifier, analog-to-digital converter, codec 211, etc. to realize the output of the envelope detection circuit 140. processing, realizing the analysis of the card reading signal, and saving two-stage operational amplifiers.
  • the microphone 230 channel of the audio codec 210 has the characteristics of high sampling rate, high precision, high out-of-band rejection ratio, etc., and the card reading performance is obviously better than the traditional circuit.
  • the MIC small-amplitude signal is amplified through the audio codec 210MIC channel, and its noise suppression ratio is extremely high, and the filtering effect to the 125KHz RF carrier is good, and the performance is better than that of the traditional operational amplifier; it can be used in electronic equipment Realize the RFID card reading function, and solve the pain point that the current electronic equipment cannot integrate this function.
  • the present application also provides an electronic device in an embodiment, including the above-mentioned audio codec 210, the above-mentioned processor 220, and the RFID card reading circuit in the above-mentioned embodiments.
  • the term “comprising”, “comprising” or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase “comprising a " does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element.
  • the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. Functions are performed, for example, the described methods may be performed in an order different from that described, and various steps may also be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

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Abstract

本申请公开了一种RFID读卡电路和电子设备，该RFID读卡电路包括：RFID线圈、线圈驱动电路、线圈谐振电容和包络检波电路，RFID线圈的第一端与线圈驱动电路的输出端连接，线圈驱动电路的输入端连接电子设备中处理器的第一控制端，线圈驱动电路用于接收处理器通过第一控制端提供的驱动信号，并在驱动信号的作用下输出第一电压信号至RFID线圈的第一端，RFID线圈用于在第一电压信号的作用下形成用于感应外部卡片的感应磁场；线圈谐振电容的一端连接RFID线圈的第二端，线圈谐振电容的另一端与直流电压端电连接；包络检波电路的输入端与RFID线圈的第二端连接，包络检波电路的输出端通过电子设备中音频编码解码器与处理器的接收端连接。

Description

RFID读卡电路和电子设备
相关申请的交叉引用
本申请主张在2021年10月27日在中国提交的中国专利申请No.202111253635.9的优先权，其全部内容通过引用包含于此。
技术领域
本申请属于射频识别技术领域，具体涉及一种RFID读卡电路和电子设备。
背景技术
射频识别(Radio Frequency Identification，RFID)技术是一种载波频率为125K-135K的近场通信识别技术，因其成本低廉，识别快速，在门禁、交通等场景有大量应用。电子设备(例如，手机等移动设备)中无线充电技术是一种基于载波频率在110K-190KHz的无线能量传输技术，为实现正确的能量传输，还伴随着通信技术。
目前，电子设备为实现射频识别，需要额外使用分立元器件搭建射频识别电路，容易导致电路布局面积较大，即搭建的电路占用面积较大。
发明内容
本申请实施例的目的是提供一种RFID读卡电路和电子设备，能够解决现有射频识别电路占用面积较大的问题。
第一方面，本申请实施例提供了所述RFID读卡电路包括：RFID线圈、线圈驱动电路、线圈谐振电容和包络检波电路，其中，
所述RFID线圈的第一端与所述线圈驱动电路的输出端连接，所述线圈驱动电路的输入端连接电子设备中处理器的第一控制端，所述线圈驱动电路用于接收所述处理器通过所述第一控制端提供的驱动信号，并在所述驱动信号的作用下输出第一电压信号至所述RFID线圈的第一端，所述RFID线圈用 于在所述第一电压信号的作用下形成用于感应外部卡片的感应磁场；
所述线圈谐振电容的一端连接所述RFID线圈的第二端，所述线圈谐振电容的另一端与低压端电连接；
所述包络检波电路的输入端与所述RFID线圈的第二端连接，所述包络检波电路的输出端通过所述电子设备中音频编码解码器与所述处理器的接收端连接，所述包络检波电路用于过滤所述RFID线圈的第二端输出的信号中的载波信号以得到基带信号，并将所述基带信号输出至所述音频编码解码器。
可选地，所述音频编码解码器包括多个麦克风接口；
所述包络检波电路的输出端连接目标麦克风接口，所述音频编码解码器的输出端与所述处理器的接收端连接，所述目标麦克风接口为所述多个麦克风接口中的任一接口；
所述包络检波电路用于将所述基带信号通过所述目标麦克风接口传输至所述音频编码解码器。
可选地，所述RFID读卡电路还包括第一开关；
所述包络检波电路的输出端连接所述第一开关的第一选择端，所述第一开关的固定端连接所述音频编码解码器的目标麦克风接口，所述第一开关的第二选择端连接麦克风，所述目标麦克风接口为所述音频编码解码器的多个麦克风接口中的任一接口，所述处理器的第二控制端连接所述第一开关的控制端；
其中，所述第一开关用于接收所述处理器通过其第二控制端提供的控制信号，并根据所述控制信号控制所述第一开关的连通状态，在所述第一选择端与所述固定端连通的情况下，所述包络检波电路通过所述第一开关与所述音频编码解码器连通，所述基带信号通过所述第一开关传输至所述音频编码解码器，在所述第二选择端与所述固定端连通的情况下，所述麦克风通过所述第一开关与所述音频编码解码器连通，所述麦克风的输出信号通过所述第一开关传输至所述音频编码解码器。
可选地，所述音频编码解码器还包括编码解码器、第一模数转换器、第 一运放器以及多路开关；
所述目标麦克风接口通过所述多路开关连接所述第一运放器的输入端，所述第一运放器的输出端连接所述第一模数转换器的输入端，所述第一模数转换器的输出端连接所述编码解码器的第一输入端，所述编码解码器的输出端连接所述处理器的接收端；
在所述目标麦克风接口通过所述多路开关连通所述第一运放器的输入端的情况下，所述目标麦克风接口将所述包络检波电路的输出端输出的所述基带信号传输至所述第一运放器的输入端，所述第一运放器用于对所述基带信号进行放大后传输至所述第一模数转换器，所述第一模数转换器用于对放大后的所述基带信号进行模数转换得到第一目标数字信号，并将所述第一目标数字信号传输至所述编码解码器，所述编码解码器用于对所述第一目标数字信号进行解码后传输至处理器。
可选地，所述音频编码解码器还包括N个第二模数转换器以及N个第二运放器，所述编码解码器包括N个第二输入端，N为正整数；
其余麦克风接口中的任一麦克风接口通过所述多路开关连接一个第二运放器的输入端，一个第二运放器的输出端通过一个第二模数转换器连接所述编码解码器的一个第二输入端，且所述N个第二运放器的输出端连接的第二模数转换器不同，以及所述N个第二模数转换器连接的第二输入端不同，所述其余麦克风接口为所述多个麦克风接口中除所述目标麦克风接口以外的接口；
在所述其余麦克风接口中的任一麦克风接口通过所述多路开关连通所述第二运放器的输入端的情况下，所述第二运放器用于对所述其余麦克风接口中的任一麦克风接口传输的信号进行放大，所述第二模数转换器用于对所述第二运放器输出的放大后的信号进行模数转换得到第二目标数字信号，并将所述第二目标数字信号传输至所述编码解码器，所述编码解码器用于对所述第二目标数字信号进行解码后传输至处理器。
可选地，所述线圈驱动电路包括N型金属氧化物半导体NMOS晶体管以 及P型金属氧化物半导体PMOS晶体管；
所述NMOS晶体管的栅极连接所述处理器的第一控制端，所述NMOS晶体管的第一极接地，所述NMOS晶体管的第二极连接所述PMOS晶体管的第一极，所述PMOS晶体管的栅极连接所述处理器的第一控制端，所述PMOS晶体管的第二极连接电源，其中，所述RFID线圈的第一端与所述线圈驱动电路中所述NMOS晶体管的第二极以及所述PMOS晶体管的第一极连接。
可选地，所述线圈驱动电路包括NPN型三极管和PNP型三极管；
所述PNP型三极管的基极连接所述处理器的第一控制端，所述PNP型三极管的第一极接地，所述PNP型三极管的第二极连接所述NPN型三极管的第二极，所述NPN型三极管的基极连接所述处理器的第一控制端，所述NPN型三极管的第一极连接电源，其中，所述RFID线圈的第一端与所述PNP型三极管的第二极以及所述NPN型三极管的第二极连接。
可选地，所述包络检波电路包括第一二极管、第二二极管、第三二极管、第一电阻、第二电阻、第一电容、第二电容和第三电容；
所述第一二极管的正极与所述RFID线圈的第二端连接，所述第一二极管的负极分别与所述第一电阻的一端、所述第一电容的一端以及所述第二电容的一端连接，所述第一电阻的另一端接地，所述第一电容的另一端接地，所述第二电容的另一端分别与所述第二电阻的一端、第三电容的一端、第二二极管的负极以及所述第三二极管的正极连接，所述第二电阻的另一端、所述第三电容的另一端、所述第二二极管的正极以及所述第三二极管的负极均接地，所述第二二极管的负极通过所述音频编码解码器与所述处理器的接收端连接。
可选地，所述RFID读卡电路还包括第三电阻，所述RFID线圈的第二端通过所述第三电阻与所述第一二极管的正极连接。
第二方面，本申请实施例还提供一种电子设备，包括音频编码解码器、处理器以及上述RFID读卡电路。
本实施例的RFID读卡电路，线圈驱动电路用于接收驱动信号，并在驱 动信号的作用下输出第一电压信号至RFID线圈的第一端，RFID线圈用于在第一电压信号的作用下形成用于感应外部卡片的感应磁场，包络检波电路用于过滤RFID线圈的第二端输出的信号中的载波信号以得到基带信号，并将基带信号输出至音频编码解码器。本实施例的RFID读卡电路，包络检波电路的输入端与RFID线圈的第二端连接，包络检波电路的输出端通过电子设备中音频编码解码器与处理器的接收端连接，实现将过滤后的基带信号通过音频编码解码器传输至处理器，也即是，本实施例方案无需额外使用分立元器件，包络检波电路复用电子设备中的音频编码解码器与处理器的接收端连接，复用音频编码解码器中的功能对包络检波电路的输出信号进行处理后传输至处理器，可减少电路中元件数量，从而减少电路占用面积。
附图说明
图1是本申请实施例提供的RFID电路的结构图之一；
图2是本申请实施例提供的RFID电路的结构图之二；
图3是本申请实施例提供的RFID电路的结构图之三；
图4是本申请实施例提供的RFID电路中线圈驱动电路的结构图之一；
图5是本申请实施例提供的RFID电路中线圈驱动电路的结构图之二；
图6是本申请实施例提供的RFID电路中包络检波电路的结构图；
图7是一种麦克风录音的语音信号图；
图8是本申请实施例提供的RFID电路中包络检波电路的第二端输出的一种基带信号图；
图9是本申请实施例提供的音频编码解码器结构图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员获得的所有其他实施 例，都属于本申请保护的范围。
本申请的说明书和权利要求书中的术语“第一”、“第二”等是用于区别类似的对象，而不用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便本申请的实施例能够以除了在这里图示或描述的那些以外的顺序实施，且“第一”、“第二”等所区分的对象通常为一类，并不限定对象的个数，例如目标对象可以是一个，也可以是多个。此外，说明书以及权利要求中“和/或”表示所连接对象的至少其中之一，字符“/”，一般表示前后关联对象是一种“或”的关系。
下面结合附图，通过具体的实施例及其应用场景对本申请实施例提供的RFID读卡电路进行详细地说明。
如图1所示，本申请提供一种实施例的一种射频识别RFID读卡电路，RFID读卡电路包括：RFID线圈110、线圈驱动电路120、线圈谐振电容130和包络检波电路140，其中，
RFID线圈110的第一端与线圈驱动电路120的输出端连接，线圈驱动电路120的输入端连接电子设备中处理器220的第一控制端，线圈驱动电路120用于接收处理器220通过第一控制端提供的驱动信号，并在驱动信号的作用下输出第一电压信号至RFID线圈110的第一端，RFID线圈110用于在第一电压信号的作用下形成用于感应外部卡片的感应磁场；
线圈谐振电容130的一端连接RFID线圈110的第二端，线圈谐振电容130的另一端与低压端电连接；
包络检波电路140的输入端与RFID线圈110的第二端连接，包络检波电路140的输出端通过电子设备中音频编码解码器210与处理器220的接收端连接，包络检波电路140用于过滤RFID线圈110的第二端输出的信号中的载波信号以得到基带信号，并将基带信号输出至音频编码解码器210。
需要说明的是，低压端可以是直流低压端，作为一个示例，低压端可以是地端，即述线圈谐振电容130的另一端可以接地。包络检波电路140可以从RFID线圈110的第二端输出的信号中将低频信号(基带信号)解调出来， 可以理解包络检波电路140具有低通滤波功能。
若没有外部卡片靠近RFID线圈110，线圈谐振电容130会和低频RFID线圈110形成谐振，在线圈谐振电容130上表现出来是振幅稳定的正弦波，例如，振荡频率可以为125khz或135khz，由于包络检波电路140是具备低通滤波功能，载波信号(例如，125khz)会被滤除，此时包络检波电路140输出给音频编码解码器210的就是一条直线，可以理解基带信号为空。若有卡片靠近RFID线圈110的感应磁场，会让线圈谐振电容130和RFID线圈110形成的谐振震荡电压有规律的变化，即RFID线圈110的第二端输出的信号会有规律的变化，该信号通过包络检波电路140进行过滤后，包络检波电路140将过滤后的基带信号输出给音频编码解码器210。音频编码解码器210(CODEC)通常由运放器、模数转换器(ADC)、数模转换器(DAC)等组成，主要为麦克风230(MIC)录音、扬声器驱动，可对信号进行放大、模数转换和数模转换等，因为电子设备有麦克风230拾音的需求，所以音频编码解码器210在现有电子设备上是一个重要配置。
本实施例的RFID读卡电路，线圈驱动电路120用于接收驱动信号，并在驱动信号的作用下输出第一电压信号至RFID线圈110的第一端，RFID线圈110用于在第一电压信号的作用下形成用于感应外部卡片的感应磁场，包络检波电路140用于过滤RFID线圈110的第二端输出的信号中的载波信号以得到基带信号，并将基带信号输出至音频编码解码器210。本实施例的RFID读卡电路，包络检波电路140的输入端与RFID线圈110的第二端连接，包络检波电路140的输出端通过电子设备中音频编码解码器210与处理器220的接收端连接，实现将过滤后的基带信号通过音频编码解码器210传输至处理器220，也即是，本实施例方案无需额外使用分立元器件，包络检波电路140复用电子设备中的音频编码解码器210与处理器220的接收端连接，复用音频编码解码器210中的功能对包络检波电路140的输出信号进行处理后传输至处理器220，可减少电路中元件数量，从而减少电路占用面积。
如图2所示，在一个实施例中，音频编码解码器包括多个麦克风接口；
包络检波电路140的输出端连接目标麦克风接口J1，音频编码解码器210的输出端与处理器220的接收端连接，目标麦克风接口J1为多个麦克风接口中的任一接口；
包络检波电路140用于将基带信号通过目标麦克风接口J1传输至音频编码解码器210。
包络检波电路140的输出端复用电子设备的音频编码解码器210的目标麦克风接口J1将其输出的信号传输至音频编码解码器210，音频编码解码器210对通过目标麦克风J1接收的包络检波电路140的输出端输出的信号进行处理后传输至处理器220，例如，音频编码解码器210对该信号进行放大和模数转换处理后传输至处理器220，无需额外设置接口传输包络检波电路140的输出端的信号，节约电路成本。即考虑到音频编码解码器210需要适时切换MIC音频通路和RFID读卡卡号通路，若音频编码解码器210有空余麦克风接口时，允许RFID读卡卡号通路与MIC通路独立设定，此情况下则不需要另外增设选通开关。另外，需要说明的是，多个麦克风接口中除目标麦克风接口J1外的其余麦克风接口中，每个麦克风接口可分别对应连接一个麦克风230。
如图3所示，在一个实施例中，RFID读卡电路还包括第一开关150；
包络检波电路140的输出端连接第一开关150的第一选择端，第一开关150的固定端连接音频编码解码器210的目标麦克风接口J1，第一开关150的第二选择端连接麦克风230，目标麦克风接口J1为音频编码解码器210的多个麦克风接口中的任一接口，处理器220的第二控制端连接第一开关150的控制端；
其中，第一开关150用于接收处理器220通过其第二控制端提供的控制信号，并根据控制信号控制第一开关150的连通状态，在第一选择端与固定端连通的情况下，包络检波电路140通过第一开关150与音频编码解码器210连通，基带信号通过第一开关150传输至音频编码解码器210，在第二选择端与固定端连通的情况下，麦克风230通过第一开关150与音频编码解码器 210连通，麦克风230的输出信号通过第一开关150传输至音频编码解码器210。音频编码解码器210的输出端与处理器220的接收端连接，音频编码解码器210可将包络检波电路140的输出端的信号或麦克风230的输出信号进行处理后传输至处理器220的接收端。
在本实施例中，考虑到CODEC可能无足够的麦克风接口，RFID读卡和音频MIC录音功能需要分时使用，例如，当需要读卡时，处理器220(可以是应用处理器220)会控制第一开关150将音频编码解码器210通路切换至RFID电路的包络检波电路140上，实现RFID读卡基带信号的放大与模数转换等；当需要实现录音等语音功能时，处理器220把第一开关150切换至音频主麦克风230通路，实现正常的语音功能。
需要说明的是，音频信号通常是20Hz～20KHz频率范围内的，音频编码解码器210的运放器、模数转换器采用设计均是基于此范围进行设计，可以将该频率范围内的信号进行放大，并且实现模数转换后送处理器220处理；而低频RFID的读卡功能，是由线圈发出125KHz或134.2KHz载波后，外部卡片在线圈感应上以约1.953KHz的速率形成负载调制，际读卡时信号经过包络检波电路140后，会把原有载波大部分滤除，剩下1.953KHz的基带信号，此信号刚好在前述音频信号20Hz～20KHz范围内，具备运放器和模数转换器采用的可行性。如图4所示，为正常的麦克风230录制的语音信号图，如图5所示，为基带信号图。
如图6所示，在一个实施例中，音频编码解码器210还包括编码解码器211、第一模数转换器212、第一运放器213以及多路开关214；
目标麦克风接口J1通过多路开关214连接第一运放器213的输入端，第一运放器213的输出端连接第一模数转换器212的输入端，第一模数转换器212的输出端连接编码解码器211的第一输入端，编码解码器211的输出端连接处理器220的接收端；
在目标麦克风接口J1通过多路开关214连通第一运放器213的输入端的情况下，目标麦克风接口J1将包络检波电路140的输出端输出的基带信号传 输至第一运放器213的输入端，第一运放器213用于对基带信号进行放大后传输至第一模数转换器212，第一模数转换器212用于对放大后的基带信号进行模数转换得到第一目标数字信号，并将第一目标数字信号传输至编码解码器211，编码解码器211用于对第一目标数字信号进行解码后传输至处理器220。
即在本实施例中，复用音频编码解码器210中的第一运放器213、第一模数转换器212和编码解码器211，可通过第一运放器213用于对基带信号进行放大后传输至第一模数转换器212，第一模数转换器212可对放大后的基带信号进行模数转换得到第一目标数字信号，并将第一目标数字信号传输至编码解码器211，编码解码器211可对第一目标数字信号进行解码后传输至处理器220，可减少额外器件的布局，减小RFID电路占用面积等。
如图6所示，在一个实施例中，音频编码解码器210还包括N个第二模数转换器215以及N个第二运放器216，编码解码器211包括N个第二输入端，N为正整数；
其余麦克风接口中的任一麦克风接口J2通过多路开关214连接一个第二运放器216的输入端，一个第二运放器216的输出端通过一个第二模数转换器215连接编码解码器211的一个第二输入端，且N个第二运放器216的输出端连接的第二模数转换器215不同，以及N个第二模数转换器215连接的第二输入端不同，其余麦克风接口为多个麦克风接口中除目标麦克风接口J1以外的接口；
在其余麦克风接口中的任一麦克风接口J2通过多路开关214连通第二运放器216的输入端的情况下，第二运放器216用于对其余麦克风接口中的任一麦克风接口J2传输的信号进行放大，第二模数转换器215用于对第二运放器216输出的放大后的信号进行模数转换得到第二目标数字信号，并将第二目标数字信号传输至编码解码器211，编码解码器211用于对第二目标数字信号进行解码后传输至处理器220。
即在本实施例中，音频编码解码器210可以通过目标麦克风接口J1连接 包络检波电路140，而且可通过其余麦克风接口连接麦克风230，麦克风230采集的信号可通过对应的麦克风接口(在通过多路开关214与第二运放器216连通的情况下)传输至第二运放器216进行放大，第二模数转换器215用于对第二运放器216输出的放大后的信号进行模数转换得到第二目标数字信号，并将第二目标数字信号传输至编码解码器211，编码解码器211用于对第二目标数字信号进行解码后传输至处理器220，实现正常的语音功能。
如图7所示，在一个实施例中，线圈驱动电路120包括N型金属氧化物半导体NMOS晶体管以及P型金属氧化物半导体PMOS晶体管；
NMOS晶体管的栅极G1连接处理器220的第一控制端，NMOS晶体管的第一极S1接地，NMOS晶体管的第二极D1连接PMOS晶体管的第一极S2，PMOS晶体管的栅极G2连接处理器220的第一控制端，PMOS晶体管的第二极D2连接电源VCC，其中，RFID线圈110的第一端与线圈驱动电路120中NMOS晶体管的第二极D1以及PMOS晶体管的第一极S2连接。
本申请所有实施例中采用的晶体管均可以为三极管、薄膜晶体管或场效应管或其他特性相同的器件。在本申请实施例中，为区分晶体管除控制极之外的两极，将其中一极称为第一极，另一极称为第二极。
在实际操作时，当晶体管为薄膜晶体管或场效应管时，控制极可以为栅极。第一极可以为漏极，第二极可以为源极；或者，第一极可以为源极，第二极可以为漏极。例如，在本实施例中，第一极可以为源极，第二极可以为漏极。
即在本实施例中，通过NMOS晶体管以及PMOS晶体管构建线圈驱动电路120，线圈驱动电路120通过NMOS晶体管的第二极或PMOS晶体管的第一极向RFID线圈110的第一端输出第一电压信号，使RFID线圈110在第一电压信号作用下形成磁场，用于感应外部卡片，以确保RFID线圈110的感应性能。
如图8所示，在一个实施例中，线圈驱动电路120包括NPN型三极管和PNP型三极管；
PNP型三极管的基极B1连接处理器220的第一控制端，PNP型三极管的第一极C1接地，PNP型三极管的第二极E1连接NPN型三极管的第二极E2，NPN型三极管的基极B2连接处理器220的第一控制端，NPN型三极管的第一极C2连接电源VCC，其中，RFID线圈110的第一端与PNP型三极管的第二极E1以及NPN型三极管的第二极E2连接。
当晶体管为三极管时，控制极可以为基极；第一极可以为集电极，第二极可以为发射极；或者，第一极可以为发射极，第二极可以为集电极。例如，在本实施例中，第一极可以为发射极，第二极可以为集电极。
即在本实施例中，通过NMOS晶体管以及PMOS晶体管构建线圈驱动电路120，线圈驱动电路120通过PNP型三极管的第二极或NPN型三极管的第二极向RFID线圈110的第一端输出第一电压信号，使RFID线圈110在第一电压信号作用下形成磁场，用于感应外部卡片，以确保RFID线圈110的感应性能。
如图9所示，在一个实施例中，包络检波电路140包括第一二极管141、第二二极管147、第三二极管148、第一电阻142、第二电阻145、第一电容143、第二电容144和第三电容146；
第一二极管141的正极与RFID线圈110的第二端连接，第一二极管141的负极分别与第一电阻142的一端、第一电容143的一端以及第二电容144的一端连接，第一电阻142的另一端接地，第一电容143的另一端接地，第二电容144的另一端分别与第二电阻145的一端、第三电容146的一端、第二二极管147的负极以及第三二极管148的正极连接，第二电阻145的另一端、第三电容146的另一端、第二二极管147的正极以及第三二极管148的负极均接地，第二二极管147的负极通过电子设备中的音频编码解码器210与处理器220的接收端连接。
可以理解，第二二极管147的负极为包络检波电路140的输出端。通过上述结构的包络检波电路140对RFID线圈110的第二端输出的信号进行过滤，以得到基带信号传输至音频编码解码器210，可提高过滤效果，从而提 高整体的RFID读卡效果。
在一个实施例中，RFID读卡电路还包括第三电阻，RFID线圈110的第二端通过第三电阻与第一二极管141的正极连接。
即RFID线圈110的第二端输出的信号可先通过第三电阻降压，然后传输至包络检波电路140中，以提高电路安全性。
本申请实施例中的RFID电路，基于共用电子设备中已集成的音频编码解码器210，利用其中的运放器、模数转换器、编码解码器211等实现对包络检波电路140的输出进行处理，实现读卡信号的解析，节省两级运算放大器，较传统采用外部独立设计的两级运算放大器电路，在布局面积要求、成本上有明显优势；较传统采用外部独立设计的两级运算放大器电路，音频编码解码器210的麦克风230通路具备高采样率，高精度，高带外抑制比等特性，读卡性能明显优于传统电路。本实施例的RFID电路中通过音频编码解码器210MIC通路针对MIC小幅度信号放大，其噪声抑制比极高，对125KHz RF载波的滤除效果好，比传统运放性能更佳；能在电子设备中实现RFID读卡功能，解决目前电子设备无法集成该功能的痛点。
本申请还提供一个实施例的电子设备，包括上述音频编码解码器210、上述处理器220以及上述各实施例中的RFID读卡电路。
需要说明的是，在本文中，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者装置不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者装置所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括该要素的过程、方法、物品或者装置中还存在另外的相同要素。此外，需要指出的是，本申请实施方式中的方法和装置的范围不限按示出或讨论的顺序来执行功能，还可包括根据所涉及的功能按基本同时的方式或按相反的顺序来执行功能，例如，可以按不同于所描述的次序来执行所描述的方法，并且还可以添加、省去、或组合各种步骤。另外，参照某些示例所描述的特征可在其他示例中被 组合。
通过以上的实施方式的描述，本领域的技术人员可以清楚地了解到上述实施例方法可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件，但很多情况下前者是更佳的实施方式。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分可以以计算机软件产品的形式体现出来，该计算机软件产品存储在一个存储介质(如ROM/RAM、磁碟、光盘)中，包括若干指令用以使得一台终端(可以是手机，计算机，服务器，或者网络设备等)执行本申请各个实施例所述的方法。
上面结合附图对本申请的实施例进行了描述，但是本申请并不局限于上述的具体实施方式，上述的具体实施方式仅仅是示意性的，而不是限制性的，本领域的普通技术人员在本申请的启示下，在不脱离本申请宗旨和权利要求所保护的范围情况下，还可做出很多形式，均属于本申请的保护之内。

Claims (10)

  1. 一种射频识别RFID读卡电路，所述RFID读卡电路包括：RFID线圈、线圈驱动电路、线圈谐振电容和包络检波电路，其中，
    所述RFID线圈的第一端与所述线圈驱动电路的输出端连接，所述线圈驱动电路的输入端连接电子设备中处理器的第一控制端，所述线圈驱动电路用于接收所述处理器通过所述第一控制端提供的驱动信号，并在所述驱动信号的作用下输出第一电压信号至所述RFID线圈的第一端，所述RFID线圈用于在所述第一电压信号的作用下形成用于感应外部卡片的感应磁场；
    所述线圈谐振电容的一端连接所述RFID线圈的第二端，所述线圈谐振电容的另一端与低压端电连接；
    所述包络检波电路的输入端与所述RFID线圈的第二端连接，所述包络检波电路的输出端通过所述电子设备中音频编码解码器与所述处理器的接收端连接，所述包络检波电路用于过滤所述RFID线圈的第二端输出的信号中的载波信号以得到基带信号，并将所述基带信号输出至所述音频编码解码器。
  2. 根据权利要求1所述的电路，其中，所述音频编码解码器包括多个麦克风接口；
    所述包络检波电路的输出端连接目标麦克风接口，所述音频编码解码器的输出端与所述处理器的接收端连接，所述目标麦克风接口为所述多个麦克风接口中的任一接口；
    所述包络检波电路用于将所述基带信号通过所述目标麦克风接口传输至所述音频编码解码器。
  3. 根据权利要求1所述的电路，其中，所述RFID读卡电路还包括第一开关；
    所述包络检波电路的输出端连接所述第一开关的第一选择端，所述第一开关的固定端连接所述音频编码解码器的目标麦克风接口，所述第一开关的 第二选择端连接麦克风，所述目标麦克风接口为所述音频编码解码器的多个麦克风接口中的任一接口，所述处理器的第二控制端连接所述第一开关的控制端；
    其中，所述第一开关用于接收所述处理器通过其第二控制端提供的控制信号，并根据所述控制信号控制所述第一开关的连通状态，在所述第一选择端与所述固定端连通的情况下，所述包络检波电路通过所述第一开关与所述音频编码解码器连通，所述基带信号通过所述第一开关传输至所述音频编码解码器，在所述第二选择端与所述固定端连通的情况下，所述麦克风通过所述第一开关与所述音频编码解码器连通，所述麦克风的输出信号通过所述第一开关传输至所述音频编码解码器。
  4. 根据权利要求2或3所述的电路，其中，所述音频编码解码器还包括编码解码器、第一模数转换器、第一运放器以及多路开关；
    所述目标麦克风接口通过所述多路开关连接所述第一运放器的输入端，所述第一运放器的输出端连接所述第一模数转换器的输入端，所述第一模数转换器的输出端连接所述编码解码器的第一输入端，所述编码解码器的输出端连接所述处理器的接收端；
    在所述目标麦克风接口通过所述多路开关连通所述第一运放器的输入端的情况下，所述目标麦克风接口将所述包络检波电路的输出端输出的所述基带信号传输至所述第一运放器的输入端，所述第一运放器用于对所述基带信号进行放大后传输至所述第一模数转换器，所述第一模数转换器用于对放大后的所述基带信号进行模数转换得到第一目标数字信号，并将所述第一目标数字信号传输至所述编码解码器，所述编码解码器用于对所述第一目标数字信号进行解码后传输至处理器。
  5. 根据权利要求4所述的电路，其中，所述音频编码解码器还包括N个第二模数转换器以及N个第二运放器，所述编码解码器包括N个第二输入端，N为正整数；
    其余麦克风接口中的任一麦克风接口通过所述多路开关连接一个第二运 放器的输入端，一个第二运放器的输出端通过一个第二模数转换器连接所述编码解码器的一个第二输入端，且所述N个第二运放器的输出端连接的第二模数转换器不同，以及所述N个第二模数转换器连接的第二输入端不同，所述其余麦克风接口为所述多个麦克风接口中除所述目标麦克风接口以外的接口；
    在所述其余麦克风接口中的任一麦克风接口通过所述多路开关连通所述第二运放器的输入端的情况下，所述第二运放器用于对所述其余麦克风接口中的任一麦克风接口传输的信号进行放大，所述第二模数转换器用于对所述第二运放器输出的放大后的信号进行模数转换得到第二目标数字信号，并将所述第二目标数字信号传输至所述编码解码器，所述编码解码器用于对所述第二目标数字信号进行解码后传输至处理器。
  6. 根据权利要求1所述的电路，其中，所述线圈驱动电路包括N型金属氧化物半导体NMOS晶体管以及P型金属氧化物半导体PMOS晶体管；
    所述NMOS晶体管的栅极连接所述处理器的第一控制端，所述NMOS晶体管的第一极接地，所述NMOS晶体管的第二极连接所述PMOS晶体管的第一极，所述PMOS晶体管的栅极连接所述处理器的第一控制端，所述PMOS晶体管的第二极连接电源，其中，所述RFID线圈的第一端与所述线圈驱动电路中所述NMOS晶体管的第二极以及所述PMOS晶体管的第一极连接。
  7. 根据权利要求1所述的电路，其中，所述线圈驱动电路包括NPN型三极管和PNP型三极管；
    所述PNP型三极管的基极连接所述处理器的第一控制端，所述PNP型三极管的第一极接地，所述PNP型三极管的第二极连接所述NPN型三极管的第二极，所述NPN型三极管的基极连接所述处理器的第一控制端，所述NPN型三极管的第一极连接电源，其中，所述RFID线圈的第一端与所述PNP型三极管的第二极以及所述NPN型三极管的第二极连接。
  8. 根据权利要求1所述的电路，其中，所述包络检波电路包括第一二极管、第二二极管、第三二极管、第一电阻、第二电阻、第一电容、第二电容 和第三电容；
    所述第一二极管的正极与所述RFID线圈的第二端连接，所述第一二极管的负极分别与所述第一电阻的一端、所述第一电容的一端以及所述第二电容的一端连接，所述第一电阻的另一端接地，所述第一电容的另一端接地，所述第二电容的另一端分别与所述第二电阻的一端、第三电容的一端、第二二极管的负极以及所述第三二极管的正极连接，所述第二电阻的另一端、所述第三电容的另一端、所述第二二极管的正极以及所述第三二极管的负极均接地，所述第二二极管的负极通过所述音频编码解码器与所述处理器的接收端连接。
  9. 根据权利要求8所述的电路，其中，所述RFID读卡电路还包括第三电阻，所述RFID线圈的第二端通过所述第三电阻与所述第一二极管的正极连接。
  10. 一种电子设备，包括音频编码解码器、处理器以及权利要求1-9中任一项所述的RFID读卡电路。
PCT/CN2022/127732 2021-10-27 2022-10-26 Rfid读卡电路和电子设备 WO2023072155A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050029351A1 (en) * 2003-06-30 2005-02-10 Matsushita Electric Industrial Co., Ltd. Noncontact IC card reader/writer
CN207882913U (zh) * 2018-02-01 2018-09-18 广州健永信息科技有限公司 一种低频rfid读卡装置
CN209216103U (zh) * 2019-01-29 2019-08-06 苏州东剑智能科技有限公司 基于分立元件的125k射频读卡电路
CN113962235A (zh) * 2021-10-27 2022-01-21 维沃移动通信有限公司 Rfid读卡电路和电子设备

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201387611Y (zh) * 2008-10-23 2010-01-20 盛惠珍 一种射频卡读写器通信电路
CN102231182B (zh) * 2010-07-28 2014-08-27 广东顶固集创家居股份有限公司 射频感应锁及其读卡模块
CN206819380U (zh) * 2017-03-24 2017-12-29 深圳市文鼎创数据科技有限公司 一种近场通信调制解调电路、安全芯片及动态令牌
CN108763984B (zh) * 2018-02-06 2022-08-16 宁波公牛电器有限公司 一种识别感应电路、控制电路及电源控制电路
CN109784457A (zh) * 2019-01-18 2019-05-21 南京南瑞继保电气有限公司 一种基于分立元器件的rfid接收电路
CN111178105B (zh) * 2019-12-31 2021-08-24 上海移为通信技术股份有限公司 一种rfid标签信息读取装置及方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050029351A1 (en) * 2003-06-30 2005-02-10 Matsushita Electric Industrial Co., Ltd. Noncontact IC card reader/writer
CN207882913U (zh) * 2018-02-01 2018-09-18 广州健永信息科技有限公司 一种低频rfid读卡装置
CN209216103U (zh) * 2019-01-29 2019-08-06 苏州东剑智能科技有限公司 基于分立元件的125k射频读卡电路
CN113962235A (zh) * 2021-10-27 2022-01-21 维沃移动通信有限公司 Rfid读卡电路和电子设备

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